TT Talk - Carrying calcium hypochlorite safely

New 'Guidelines for the Carriage of Calcium Hypochlorite in Containers' are intended to allow the carriage of calcium hypochlorite under controlled circumstances, to ensure that it is properly declared, packaged, packed and carried.


TT Talks

have drawn attention to the problems that have historically been encountered with the carriage of 'Calcium Hypochlorite'. The most significant cases occurred at the end of the 1990s ('DG Harmony', 'CMA Djakarta' and 'Aconcagua'), which demonstrated the risks to seafarers and others, as well as the willingness of certain cargo interests to mis-declare the cargo or maintain improper production processes.

Following another spate of fires over the last couple of years emanating from this highly sensitive cargo, the


(Cargo Incident Notification System) Organisation set about collaborating with the


(International Group of P&I Clubs) to update and clarify the guidance that had last been revised in 2011. Drawing together a broad spectrum of stakeholders (including TT Club), a working group sought better information about the inherent characteristics of the cargo in order to compile revised guidelines intended to be acceptable across the container shipping industry and for related insurers.

The character of the cargo

The benefits of chlorine as an agent to kill most disease-causing bacteria, even at relatively low concentrations, are widely recognised. Global production of calcium hypochlorite is thought to be about 400,000 tonnes per year, much of which is exported. It is commonly used as a recreational and industrial water cleanser and disinfectant, and particularly important for drinking water and wastewater purification. As such, its value is broad - from swimming pools, through military kits to humanitarian relief efforts.

However, the chlorine element is a powerful oxidiser, prone to combustion. As the product decomposes, it produces heat, oxygen and chlorine gas. The decomposition reaction - taking place constantly at a very slow rate - is accelerated by higher temperatures and by contamination. The sources of contamination leading to exothermic reaction may be from water (moisture), organic materials or metals. As a result, it is extremely important for producers to maintain rigorous controls over the raw materials used and the entire manufacturing process, as well as to consider carefully the packaging required for the intended market (taking account of the associated transport).

“it is extremely important for producers to maintain rigorous controls over the raw materials used and the entire manufacturing process”

Investigations into many fire incidents have too often implicated this cargo, almost always in the same breath as being critical of the manner in which it has been produced, packed, marked or declared through the supply chain. The potential for disastrous impact from this and similar cargoes is well demonstrated through the analysis released by the CINS Organisation, which shows that 32% of all incidents are found to relate to mis-declaration and more than 75% to the entirety of the packing process. While clearly few incidents for the CINS membership - which now includes almost 70% of the global container line slot capacity - relate to calcium hypochlorite, and indeed more than two thirds of the incidents are not formally concerning dangerous goods, the adjacency risk on board container ships means that many inert cargoes are susceptible to fuel fire, if one occurs.

Process control measures

There is limited oversight that any carrier can hope to have in relation to the efficacy of a production process. As a result, concentrating on the potential for mis-declaration and improper packing is important. For carriers this can be achieved through rigorous booking processes (perhaps adopting an approach such as

Hapag-Lloyd’s ‘Watchdog’

or by implementing an inspection programme for packed containers prior to accepting them on board.

“concentrating on the potential for mis-declaration and improper packing is important”


Code of practice for packing cargo transport units

(CTU Code) states:

‘Although the carrier generally, in a contract of carriage, is responsible under that contract to deliver the cargo in the same condition as received, it is the shipper who should deliver a cargo which is safe and suitable for transport…Within this chain of responsibilities, each party in the chain should comply with their individual responsibilities and in doing so increase safety and reduce the risk of injury to persons involved in the supply chain’. 

Container lines have made significant efforts to eliminate the problems arising from mis-declaration of this cargo, but it has still been implicated in too many ship fires recently. The risk exposure has led some lines to impose strict carriage precautions or even outright carriage bans. Given the large quantities of calcium hypochlorite that are shipped each year, there is an obvious desire both to discourage mis-declaration by shippers and to encourage shipping lines' confidence in the carriage of properly declared calcium hypochlorite under an acceptable method.

Welcome safety guidance

The new


provide logical step-by-step guidance, starting with the cargo hazards and categorization under the IMDG Code, through to issues concerning container selection, container packing and stowage on a ship. Key amongst the recommendations are the use of plastic drums with adequate air circulation, a package limit of 45 kg net weight and a limit on the maximum payload per container not exceeding 14 tonnes. Dry or reefer containers may be used - provided that a proper risk assessment is undertaken.

We hope that you have found the above interesting. If you would like further information, or have any comments, please email us, or take this opportunity to forward to any colleagues who you may feel would be interested.

We look forward to hearing from you.

Peregrine Storrs-Fox

Risk Management Director, TT Club

Staff Author

TT Club